Final answer:
The appropriate form of the verb 'gustar' to fill in the blank is 'gustaban'. 'Gustaban' agrees with the plural subject 'nada' (nothing) in the sentence.
Step-by-step explanation:
The appropriate form of the verb 'gustar' to fill in the blank is 'gustaban'.
The sentence 'Recuerdo que, cuando Ana era pequeña, a ella no le (gustar) nada' translates to 'I remember that when Ana was little, she didn't like anything.'
'Gustaban' is the correct form because it agrees with the plural subject 'nada' (nothing) in the sentence.
Learn more about Verb conjugation in Spanish